This invention relates generally to slide fasteners, more particularly to reinforcements secured to a longitudinal edge of a stringer tape and adapted to mount thereon a row of interlocking elements of the fastener.
There have been proposed a number of tape edge reinforcements which are adapted to reinforce the tape edge along which the fastener elements are mounted and to provide positional stability of the latter during their coupling and uncoupling operation. Most widely used reinforcements were in the form of a plurality of yarns twisted or stranded substantially into a cross-sectionally circular configuration. The inherent drawback of this type of reinforcement is that it is susceptible to wear, rupture or other deformation when subjected to distorted stresses for instance as in the case where the reinforcement is held in vigorous contact with the fastener elements which are usually made of highly rigid materials such as metal or synthetic resin. Another known tape edge reinforcement was an elongate core enveloped by a weft-knit tubular fabric. However, due to the tendency of the weft-knitted fabric to expand and contract circumferentially of the tube, the core was liable to get loose and disunited therefrom. Thus, these prior-art reinforcements were not quite satisfactory for the purpose of retaining the fastener elements in the proper position and posture.